1. Field of the Invention
With reference to the classification of art as established in the United States Patent and Trademark Office, the present invention is believed to be found in the general Class entitled, "Metallic Receptacles" (Class 220) and in the subclass entitled, "sectional" (subclass 4.0) and in the further subclass entitled, "stacked" (subclass 4C) and the subclass "knockdown" (subclass 4F).
Although this classification pertains to metallic containers, the pallet and container structure is generally found in the subclass and subclasses above-noted.
2. Description of the Prior Art
The use of plastic moldings in containers is well known and the molding of pallets from plastic is also a recently accomplished fact. Patents directed toward pallet container combinations made of plastic and as found in the pre-Ex search are: U.S. Pat. No. 3,416,692 to CLINE, et al., as issued on Dec. 17, 1968; U.S. Pat. No. 3,985,258 to QUIGLEY as issued on Oct. 12, 1976 and U.S. Pat. No. 4,000,827 as issued to EMERY on Jan. 4, 1977.
It is to be noted that CLINE shows a shipping container of plastic construction. This container does not show a pallet with a four-way fork lift opening or a one-piece construction. The QUIGLEY patent shows a pallet-container which provides a four-way entry for forks of a lift truck. The container as described and claimed is a knockdown unit with the sides removable from the bottom. Although a four-way pallet form is provided, this pallet is not unitarily molded but is reinforced by skid bars secured by screws. This container has no provision for the stacking and retaining of one pallet-container on another of a like size and configuration. The side panels in this showing are not tapered and ribbed to provide maximum strength for the supplied amount of plastic.
In U.S. Pat. No. 4,000,827 to EMERY the sides of the container are made of a like size and configuration. They are joined by screws at the corners and also to the bottom to provide the finished container. Only a two-sided opening for the entry of forks of a lift truck is provided. There is no contemplation of stacking of the container of EMERY nor provision for retaining such containers in a positive nested relationship if they are so stacked.
In the present invention there is provided a one-piece molded pallet-container usually having a four-way entrance capacity for a pair of forks of and on a lift truck. The pallet bottom is ribbed to provide the strength for lifting a loaded pallet by such forks. The sides of the container are vertically ribbed with tapering ribs to provide the side strength needed for fluid or near fluid loads. Horizontal ribbing is also provided to provide the desired stiffness and strength to resist side forces when a load is placed in the container. The bottom outer edge is reduced and contoured so as to provide a stacking capability. This stacking and nesting is easy and positive and at the seating shoulder is contoured to provide a four-way seating of one container on another.
In these and other known embodiments there has not been provided a one-piece pallet container of a large size such as a width of forty-four inches (1117.6 mm.), a length of forty-eight inches (1219.2 mm.) and a height of twenty-eight inches (711.2 mm.). As reduced to practice, a pallet container of a one-piece molding having the above width, length and height has been produced. The embodiment to be more fully described, in addition to a pallet-container of one piece, also contemplates that the mold may be provided with shut-off inserts to provide selectively positioned drain holes in the formed bottom and/or vent slots in the side walls.
The one-piece container also is formed at its top rim with a shoulder that is sized to be compatible with and retain a pallet-container when stacked thereon. The retaining rims and shoulders are formed to provide a shallow but positive seating and retaining of one pallet-container or another of like size and configuration. A separate one-piece molded cover member is contemplated and may be provided to protect the contents as stored in the container portion.
Although the above-mentioned pallet-container has a rectangular configuration, this is not to say that these sizes and configurations are the only sizes and configurations. For example, contemplated sizes include forty-four inches (1117.6 mm.) in width by forty-eight inches (1219.2 mm.) long by forty-two inches (1066.8 mm.) high. Other size containers may have a width of forty inches (1016 mm.), a length of forty-eight inches (1219.2 mm.) and a height of forty-two inches (1066.8 mm.). Other containers are forty (1016.0 mm.) by forty-eight (1219.2 mm.) by twenty-eight and three-quarter inches (730.25 mm.). Other pallet-containers are forty-seven inches square (1193.8 mm.) with one container twenty-eight and three-quarter inches (730.25 mm.) high and another container forty-two inches (1066.8 mm.) high. The foam plastic can be any thermoplastic material such as polycarbonate, polypropylene, polyacetal, polyamid, or polyphenylene oxide but most commonly high density polyethylene.